monkey-wasm 1.0.0

mod utils;

use crate::utils::set_panic_hook;
use compiler::compiler::Compiler;
use compiler::snapshot::{read_bytecode, write_bytecode};
use compiler::snapshot_layout::describe_bytecode;
use parser::parse as parser_pase;
use parser::parse_ast_json_string;
use wasm_bindgen::prelude::*;
use wasm_bindgen::throw_str;

const PLAYGROUND_GC_INSTRUCTION_BUDGET: usize = 10_000;

// When the `wee_alloc` feature is enabled, use `wee_alloc` as the global
// allocator.
#[cfg(feature = "wee_alloc")]
#[global_allocator]
static ALLOC: wee_alloc::WeeAlloc = wee_alloc::WeeAlloc::INIT;

#[wasm_bindgen]
pub fn parse(input: &str) -> String {
    set_panic_hook();
    match parse_ast_json_string(input) {
        Ok(node) => node.to_string(),
        Err(e) => throw_str(format!("parse error: {}", e[0]).as_str()),
    }
}

#[wasm_bindgen]
pub fn compile(input: &str) -> String {
    set_panic_hook();

    let program = match parser_pase(input) {
        Ok(ast) => ast,
        Err(e) => throw_str(format!("parse error: {}", e[0]).as_str()),
    };
    let mut compiler = Compiler::new();
    match compiler.compile(&program) {
        Ok(bytecode) => return bytecode.instructions.string(),
        Err(e) => throw_str(format!("compile error: {}", e).as_str()),
    }
}

#[wasm_bindgen]
pub fn compile_detail(input: &str) -> String {
    set_panic_hook();

    let program = match parser_pase(input) {
        Ok(ast) => ast,
        Err(e) => throw_str(format!("parse error: {}", e[0]).as_str()),
    };
    let mut compiler = Compiler::new();
    match compiler.compile(&program) {
        Ok(bytecode) => return bytecode.string(),
        Err(e) => throw_str(format!("compile error: {}", e).as_str()),
    }
}

#[wasm_bindgen]
pub fn compile_with_debug(input: &str) -> String {
    set_panic_hook();

    let program = match parser_pase(input) {
        Ok(ast) => ast,
        Err(e) => throw_str(format!("parse error: {}", e[0]).as_str()),
    };
    let mut compiler = Compiler::new();
    match compiler.compile(&program) {
        Ok(bytecode) => match serde_json::to_string(&bytecode.debug_view()) {
            Ok(json) => json,
            Err(e) => throw_str(format!("json error: {}", e).as_str()),
        },
        Err(e) => throw_str(format!("compile error: {}", e).as_str()),
    }
}

/// Execute Monkey source on the cycle-collecting VM and return a tagged JSON envelope.
///
/// User parse, compile, runtime, and execution-limit failures are data in the envelope,
/// not JavaScript exceptions. This keeps the playground's Run GC path deterministic.
#[wasm_bindgen]
pub fn run_gc_with_report(input: &str) -> String {
    set_panic_hook();

    let envelope = match gc::run_source_with_report(input, PLAYGROUND_GC_INSTRUCTION_BUDGET) {
        Ok(success) => serde_json::json!({
            "status": "ok",
            "result": success.result,
            "report": success.report,
        }),
        Err(error) => serde_json::json!({
            "status": "error",
            "stage": error.stage,
            "message": error.message,
            "span": error.span,
        }),
    };

    serde_json::to_string(&envelope).expect("GC run envelope serialization should not fail")
}

/// Compile Monkey source into a `.mbc` snapshot and return a tagged JSON envelope
/// with the raw bytes (lowercase hex) plus a byte-range annotation of the container
/// layout for the playground inspector.
///
/// User parse and compile failures are data in the envelope, not JavaScript
/// exceptions, mirroring [`run_gc_with_report`].
#[wasm_bindgen]
pub fn compile_to_snapshot(input: &str, strip_debug: bool) -> String {
    set_panic_hook();

    let envelope = match snapshot_envelope(input, strip_debug) {
        Ok(envelope) => envelope,
        Err((stage, message)) => serde_json::json!({
            "status": "error",
            "stage": stage,
            "message": message,
        }),
    };
    serde_json::to_string(&envelope).expect("snapshot envelope serialization should not fail")
}

fn snapshot_envelope(
    input: &str,
    strip_debug: bool,
) -> Result<serde_json::Value, (&'static str, String)> {
    let program = parser_pase(input).map_err(|errors| {
        let message = errors
            .first()
            .cloned()
            .unwrap_or_else(|| "unknown parse error".to_string());
        ("parse", message)
    })?;
    let mut compiler = Compiler::new();
    let bytecode = compiler
        .compile(&program)
        .map_err(|message| ("compile", message))?;
    let bytes = write_bytecode(&bytecode, strip_debug)
        .map_err(|error| ("snapshot", format!("{:?}", error)))?;
    let layout = describe_bytecode(&bytes).map_err(|error| ("snapshot", format!("{:?}", error)))?;
    Ok(serde_json::json!({
        "status": "ok",
        "bytesHex": hex_encode(&bytes),
        "layout": layout,
    }))
}

fn hex_encode(bytes: &[u8]) -> String {
    use std::fmt::Write;

    let mut out = String::with_capacity(bytes.len() * 2);
    for byte in bytes {
        write!(out, "{:02x}", byte).expect("writing to a String cannot fail");
    }
    out
}

/// Execute `.mbc` snapshot bytes on the cycle-collecting VM — the browser twin of
/// `monkey-gc run foo.mbc`, sharing its execution path (`gc::run_bytecode`).
///
/// The buffer is untrusted input: it goes through the validating snapshot reader
/// before the VM. Failures are data in the envelope — stage `snapshot` when the
/// bytes are rejected, `runtime` when the VM errors (the span is only present
/// when the snapshot kept its debug info).
#[wasm_bindgen]
pub fn run_snapshot(bytes: &[u8]) -> String {
    set_panic_hook();

    let envelope = match read_bytecode(bytes) {
        Ok(bytecode) => match gc::run_bytecode(bytecode, PLAYGROUND_GC_INSTRUCTION_BUDGET) {
            Ok(result) => serde_json::json!({
                "status": "ok",
                "result": result,
            }),
            Err(error) => serde_json::json!({
                "status": "error",
                "stage": "runtime",
                "message": error.message,
                "span": error.span,
            }),
        },
        Err(error) => serde_json::json!({
            "status": "error",
            "stage": "snapshot",
            "message": format!("{:?}", error),
            "span": null,
        }),
    };
    serde_json::to_string(&envelope).expect("snapshot run envelope serialization should not fail")
}